In battery-driven information terminals in recently widespread use, maximum peak power consumed by the entire apparatus is important in terms of battery capacity design, and there has been developed a maximum peak power-suppressing art achievable by prohibiting the concurrent use of a variety of peripheral devices in the apparatus. For example, cited Reference No. 1, published Japanese Patent Application Laid-Open No. (HEI) 9-237138, discloses an art in which there is provided a block for queuing a request made by a processor to operate peripheral devices, whereby the peripheral devices have a total power consumption value controllably maintained within a certain value.
FIG. 20 is a block diagram illustrating a prior art power consumption-managing apparatus. FIG. 20 is a simplified block diagram based on FIG. 4 disclosed by cited Reference No. 1. The power consumption-managing apparatus includes a processor 1, devices 3, 4, and 5 such as a FDD, CD-ROM, and HDD, and a power-managing unit 2. The processor 1 is operable to execute several threads. Each of the threads makes a request to the power-managing unit 2 for the use of any one of the devices 3-5. The power-managing unit 2 includes a queue-controlling program operable to manage the power consumption of each of the devices. The program sends out a permitted request to each control program in the devices 3-5, such that a total power consumption value required for all of the permitted requests remains within the maximum system power source value.
FIG. 21 is a diagram illustrating a control sequence of the prior art power consumption-managing apparatus. The following discusses in detail, with reference to the control sequence diagram of FIG. 21, a power consumption-controlling method for use in the prior art power consumption-managing apparatus of FIG. 20.
The processor 1 determines a course of action to be provided by the device 3. At time “T1”, the processor 1 sends out a request for the use of the device 3 to the power-managing unit 2. The power-managing unit 2 queues the use request from the processor 1 in a waiting line. When the use request comes to the head of the queuing, then the power-managing unit 2 ascertains that a total power consumption value of all of the operating devices including the target device 3 is equal to or smaller than the maximum system power source value. At time “T2”, the power-managing unit 2 sends the use request to the device 3. The device 3 in receipt of the use request from the power-managing unit 2 performs a predetermined course of action. When completing the course of action, then at time “T3”, the device 3 sends a completion notification on the course of action to the power-managing unit 2. At time “T4”, the power-managing unit 2 sends a notification of the completed use of the device 3 to the processor 1.
As described above, when using the peripheral devices, the prior art power consumption-managing apparatus has control of the maximum power consumption in such a manner that the maximum power consumption is limited to at most the maximum power value of a system power source. However, as illustrated in FIG. 21, according to the prior art construction, the processor 1 that addressed the device use request is impossible to exactly understand how long the request is held in the waiting line by the power-managing unit 2. This means that there is a problem in that the devices are objectionably operated in accordance with already received, pre-updated information, even when data to be sent to the device 3 is updated or otherwise cancelled during the queuing. In addition, the processor 1 is impossible to grasp how the device use request is being handled, until receiving the completion notification that the device 3 has completed the course of action. Furthermore, the several devices 3-5 cannot be used in the order of device use priority.
In view of the above, an object of the present invention is to provide an electrical power-managing art operable to provide controlled peak power to an electronic apparatus including several processors and several devices, and operable to operate the devices in accordance with constantly updated information.